Last trip to the lake started my motor, ran for about 3 min.& died. Tried to start it by turning the key (nothining, no power to the key). checked the fuse on the motor (it was blown). disc. the batt. & replaced the fuse. Reconected the batt. instantley blown fuse. Motor is an 83-84 yamaha 90horse AETO. not sure whats causing the prob. Any sugg. would greatly appreciated.